Rebuttal to Attack Against Carnitine

On April 13, 2013, a meta-analysis performed by the Mayo Clinic was released that looked at 3,600 patients and found huge cardiac benefits in those who supplemented with L-carnitine.1 This study represented the largest, most powerful scientific review of carnitine’s cardiovascular benefits to date.

The Mayo Clinic study found carnitine supplementation was associated with a 27% reduction in all-cause mortality, a 65% reduction in ventricular arrhythmias, and a40% reductionin angina symptoms in patients who had experienced a heart attack.1 The media largely overlooked this favorable report, however.

Instead, headline news stories were created based on a report released a week earlier that had asserted that carnitine (found in red meat) may react with certain gut bacteria in certain individuals to promote a compound (TMAO) that could then cause heart disease.2

These carnitine findings were based on a sub-study of 10 people.2 They were obscure, theoretical, and preliminary. Yet the media ignored hundreds of studies showing significant cardiovascular benefits to carnitine, choosing instead to use this study in isolation to bash anything that contained carnitine.

Life Extension® has thoroughly analyzed the report used by the media to attack carnitine, reviewed the published literature on carnitine and heart disease, and conducted a survey of our members using carnitine. It may not surprise you to learn that our findings contradict the mainstream’s propagandized carnitine attack. This article contains a scientific rebuttal to this recent attack on carnitine.

As a Life Extension member, I hope you appreciate discovering the facts behind misleading reports spewing from today’s headline-frenzied media.

A recent investigational study published in the journal Nature Medicine examined levels of a compound called trimethylamine-N-oxide (TMAO) in relationship to microbial metabolism of carnitine in the gut.2 The researchers cite very recent, limited research suggesting TMAO may be a risk factor for cardiovascular disease. They then provocatively propose that carnitine consumption may increase cardiovascular risk in some individuals due to increasing TMAO levels following microbial metabolism of the compound.

The authors report the intestinal bacterial flora of people who consume red meat, a significant source of dietary carnitine, was conducive to TMAO production in the presence of carnitine, whereas vegetarians produced little to no TMAO under the same circumstances. They concluded that alterations in the intestinal microbiota associated with meat consumption may promote the formation of TMAO from dietary carnitine, and therefore suggested that the high carnitine content of red meat may be one of the reasons it is linked to heart disease.2

Following publication of this study, mainstream media outlets propagated misleading headlines blaming carnitine for heart disease without explaining that these findings were very preliminary and that red meat consumption was required for the observed effect.3-5 Life Extension members are well aware of the potential health threats associated with red meat consumption, such as exposure to saturated fats and advanced glycation end products,6 and may already consume heart-healthy, fish/plant-based foods contained in the Mediterranean diet.

These deceptive media headlines have generated concern that supplemental forms of L-carnitine may be detrimental to heart health. This notion flies in the face of numerous published, peer-reviewed studies showing L-carnitine promotes cardiovascular health in a variety of ways. The media’s effort to generate outrageous headlines has undermined decades of scientific research on the heart-health benefits of carnitine.

Ironically, days after publication of the carnitine article in Nature Medicine, a meta-analysis of the research on carnitine and heart health was published by researchers from the Mayo Clinic.1This large systematic review provides strong evidence for carnitine’s benefits in heart health. This article examined 13 controlled trials that enrolled, collectively, 3,629 participants, representing the largest, most powerful scientific review of carnitine’s cardiovascular benefits to date.

The authors of the Mayo Clinic study found carnitine supplementation was associated with a 27% reduction in all-cause mortality, a 65% reduction in ventricular arrhythmias, and a 40% reduction in angina symptoms in patients experiencing a heart attack.1These effects were thought to occur through multiple mechanisms, including improved energy metabolism in the mitochondria, decreased ischemia, and enhanced left ventricle function.

The authors describe carnitine as an inexpensive therapy with an “excellent safety profile” which could potentially be used in patients with angina or who are at risk for angina after suffering from a heart attack.1 Based on the results of this meta-analysis, the authors suggest L-carnitine as a potential future therapy for heart attack and secondary coronary prevention and treatment, including angina. The scientists state: “Further study with large randomized controlled trials of this inexpensive and safe therapy in the modern era is warranted.” Unfortunately they also note: “However, a large trial may never be performed because L-carnitine is an over-the counter supplement available to the public, which decreases the potential revenue compared with a synthesized [pharmaceutical] product.” 1

Carnitine’s benefits are well established and Life Extension has written about them at length over the years. The next several paragraphs describe some of the key health benefits associated with carnitine.

Carnitine Reduces Death Rates

The heart muscle uses fat as its primary energy source. Carnitine is a fat-transporting compound that is absolutely essential for normal heart function. 1,7 Over time, the decline of carnitine plays a role in the weakening of the heart’s muscles.8

People with heart muscle damage due to heart attacks or heart failure have especially low carnitine levels.9-11 Fortunately, carnitine supplementation has proven to be remarkably effective in fighting and even reversing the heart-weakening effects of that drop.8

In one study, 160 male and female heart attack survivors between 39 and 86 years old received either 4 grams/day of L-carnitine or a placebo for 12 months.12 The patients taking L-carnitine experienced significantly favorable decreases in heart rate and blood pressure; they also had improved blood lipid profiles. Most importantly, those supplementing with carnitine had a dramatically reduced death rate compared to those not taking carnitine. Patients taking carnitine had a death rate of just 1.2% in the entire year, while 12.5% of control patients died, with the majority of deaths attributed to repeat heart attacks .12

L-carnitine supplementation also prevents the progression of heart muscle damage in people with congestive heart failure and improves exercise tolerance in people who develop chest pain (angina) with exertion.9 In one study, 55% of patients experienced improvement in their standard heart failure classification .9

These statements have not been evaluated by the Food and Drug Administration.
These products are not intended to diagnose, treat, cure, or prevent any disease.

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